Resolution

Create a new
list view by clicking the
+ icon next to the current
All view on the main Jenkins homepage.

Enable the options
Filter build queue and
Filter build executors. These options will allow the build queue and build executors to show only those that are related to the jobs selected.

Select the jobs that are to be shown by this view. Note, if this view is to replace the current
All view, select all jobs or use an appropriate regular expressions to select all jobs. You may further restrict users based on
role permissions or
user permissions.

Configure jobs to be restricted on particular agents to have the view filter on only these agents.

Comparing this with the original
All view above, you will see only one executor present.

Lastly, to remove the previous default
All view, go to
Jenkins >
Manage Jenkins >
Configure System >
Default View and select your new filtered view. This option is only available when there are more than one
list view available. Once you have selected the new default view, you may go back to the old
All view and
Delete view.